Need help identifying a used lens (new to LF photo)

I'm just beginning in LF photography thanks to a friend who gave me his old (25 years +) LF equipment. One of he peices of equipment that he gave me is a WA lens of unknown focal length. I'm trying to identify the focal length of this lens. The lens has the following markings:

Schneider - Kreuznach
Angulon 1:6,8/90
5496435

Any help with this or pointers to resources for finding information about the lens would be greatly appreciated.

One other quesiton - There seems to be an indication that the min aperature is f/90 but the aperature ring only has markings to f/32.

Answers

It's a Schneider Angulon 90mm f/6.8 wide angle lens and was made
sometime between Feb '57 and May '59. If it's in good condition it'll
be a decent performer on 4x5. Do a Google search on "Angulon" to find
out more info.

Manufacturer is Schneider - Kreuznach is the name of the manufacturer
1:6,8 means the largest aperture is f 6.8 (Many European countries
interchange "."s and ","s in number from the US/British way.
(Japanese use 10,000's instead of 1,000's for groupings so these
things vary with different cultures.)

90 = the focal length of the lens, not the smallest aperture.

Angulon is the name of the lens design

The other number is probably the serial number.

I have a 90mm Angulon, too, which I like. It has virtually no spare
image circle for movements, but straight on it performs well for me.